Geotemporal Fluorophore Biodistribution Mapping of Colorectal Cancer: Micro and Macroscopic Insights.

Fluorescence-guided oncology promises to improve both the detection and treatment of malignancy. We sought to investigate the temporal distribution of indocyanine green (ICG), an exogenous fluorophore in human colorectal cancer. This analysis aims to enhance our understanding of ICG's effectiveness in current tumour detection and inform potential future diagnostic and therapeutic enhancements. METHODS: Fifty consenting patients undergoing treatment for suspected/confirmed colorectal neoplasia provided near infrared (NIR) video and imagery of transanally recorded and ex vivo resected rectal lesions following intravenous ICG administration (0.25 mg/kg), with a subgroup providing tissue samples for microscopic (including near infrared) analysis. Computer vision techniques detailed macroscopic 'early' (<15 min post ICG administration) and 'late' (>2 h) tissue fluorescence appearances from surgical imagery with digital NIR scanning (Licor, Lincoln, NE, USA) and from microscopic analysis (Nikon, Tokyo, Japan) undertaken by a consultant pathologist detailing tissue-level fluorescence distribution over the same time. RESULTS: Significant intra-tumoural fluorescence heterogeneity was seen 'early' in malignant versus benign lesions. In all 'early' samples, fluorescence was predominantly within the tissue stroma, with uptake within plasma cells, blood vessels and lymphatics, but not within malignant or healthy glands. At 'late' stage observation, fluorescence was visualised non-uniformly within the intracellular cytoplasm of malignant tissue but not retained in benign glands. Fluorescence also accumulated within any present peritumoural inflammatory tissue. CONCLUSION: This study demonstrates the time course diffusion patterns of ICG through both benign and malignant tumours in vivo in human patients at both macroscopic and microscopic levels, demonstrating important cellular drivers and features of geolocalisation and how they differ longitudinally after exposure to ICG.

Parathormone response to thyroid surgery.

BACKGROUND: Confident determination of adequate residual parathyroid function early after thyroid surgery could facilitate the discharge of patients soon after their operation without the need for subsequent serum calcium monitoring and/or calcium and vitamin D supplementation. METHODS: Thirty-one patients who underwent 33 thyroid operations (22 unilateral lobectomies and 11 bilateral thyroid resections) were prospectively studied. Parathormone (PTH) levels were measured intraoperatively, and serum calcium was monitored before and after surgery to determine PTH and calcium homeostatic response to thyroid surgery. RESULTS: A significant decrease in circulating PTH occurred during 27 procedures, most markedly after specimen mobilization. Intraoperative PTH and postoperative calcium levels were lowest in those who underwent bilateral operations. Patients who underwent unilateral procedures experienced significant decreases in PTH but not postoperative calcium levels. A PTH level >50% of baseline predicted normocalcemia by postoperative day 3. However, PTH level did not accurately triage other patients' risk for postoperative hypocalcemia. CONCLUSIONS: A decrease in PTH levels intraoperatively is a common event during both unilateral and bilateral thyroid operations. Although normal PTH levels at the end of surgery ensure normocalcemia after surgery, patients with low final PTH measurements may not develop significant hypocalcemia after surgery.